1. Field of the Invention
The present invention relates to adjustable height portable tables, and, more particularly, to a portable table which can be easily raised or lowered by using a jack.
2. Description of Related Art
Recently there has become a need to have a portable and easily adjustable table which can vary its height. For the reasons discussed below, the table must be extremely stable and, in addition, be free from any type of clutter beneath its supporting surface. Such tables can find use in various environments, such as in offices, restaurants, factories and machine shops. For example, if the table were to be used as a welding fixture to support articles as they are welded together, it would be very important for the table to have all of the above-mentioned features. Therefore, it would be important that the table be portable so that it may be moved to whatever part of the shop that the welding is to be done. The table has to be extremely stable so that the table does not jostle, for example, when its height is being adjusted, and the table needs to be fairly clear from clutter so that various items, such as tanks for the welding equipment, can be stored underneath the table. Of particular importance, of course, is the ability for the table to adjust its height so that welding personnel can easily access various parts of equipment being worked on. Previously designs of a welding fixture were typically a fixed table which, since it could not be moved from place to place or have its height adjusted, are not satisfactory.
Another proposed solution to the problem is to use a certain type of jack to make a welding table adjustable. Such a jack typically is simply removed, for example, from a trailer hitch and placed on a two part table so that when the jack is actuated, the table top moves up and down. This of course suffers from a major drawback in that the jack is so incredibly large that it takes up all storage space under the table and tends to be of a clumsy design.
Yet another proposal to overcome the problems stated in the prior art is represented by U.S. Pat. No. 5,437,236 which discloses a multi-functional table with elevational capabilities. In that patent, there is proposed the use of a hydraulic jack between a base and a table top. This arrangement is considered to suffer two major disadvantages in that, first of all, the table is not portable and may not be easily moved from place to place in a machine shop and, more importantly, the table is not stable. While the patent does recognize its own deficiency in the table not being stable enough and does try to correct the situation by proposing using four telescoping supports as shown in FIG. 13, it is still woefully lacking in any type of frame structure which would provide the necessary support for proper welding work.
Accordingly, it is desirable to provide a portable, adjustable height table which does not suffer the drawbacks mentioned above and furthermore is easily adjustable in height, readily portable, and lacks any type of clutter below its main support surface.